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dc.contributor.authorKlöcking, M
dc.contributor.authorWhite, NJ
dc.contributor.authorMaclennan, J
dc.contributor.authorMcKenzie, D
dc.contributor.authorFitton, JG
dc.date.accessioned2019-01-11T00:32:06Z
dc.date.available2019-01-11T00:32:06Z
dc.date.issued2018
dc.identifier.issn1525-2027
dc.identifier.urihttps://www.repository.cam.ac.uk/handle/1810/287844
dc.description.abstract©2018. American Geophysical Union. All Rights Reserved. Western North America has an average elevation that is ∼2 km higher than cratonic North America. This difference coincides with a westward decrease in average lithospheric thickness from ∼240 to <100 km. Tomographic models show that slow shear wave velocity anomalies lie beneath this region, coinciding with the pattern of basaltic magmatism. To investigate relationships between magmatism, shear wave velocity, and temperature, we analyzed a suite of >260 basaltic samples. Forward and inverse modeling of carefully selected major, trace, and rare earth elements were used to determine melt fraction as a function of depth. Basaltic melt appears to have been generated by adiabatic decompression of dry peridotite with asthenospheric potential temperatures of 1340 ± 20 °C. Potential temperatures as high as 1365 °C were obtained for the Snake River Plain. For the youngest (i.e., <5 Ma) basalts with a subplate geochemical signature, there is a positive correlation between shear wave velocities and trace element ratios such as La/Yb. The significance of this correlation is explored by converting shear wave velocity into temperature using a global empirical parameterization. Calculated temperatures agree with those determined by inverse modeling of rare earth elements. We propose that regional epeirogenic uplift of western North America is principally maintained by widespread asthenospheric temperature anomalies lying beneath a lithospheric plate, which is considerably thinner than it was in Late Cretaceous times. Our proposal accounts for the distribution and composition of basaltic magmatism and is consistent with regional heat flow anomalies.
dc.publisherAmerican Geophysical Union (AGU)
dc.titleQuantitative Relationships Between Basalt Geochemistry, Shear Wave Velocity, and Asthenospheric Temperature Beneath Western North America
dc.typeArticle
prism.endingPage3404
prism.issueIdentifier9
prism.publicationDate2018
prism.publicationNameGeochemistry, Geophysics, Geosystems
prism.startingPage3376
prism.volume19
dc.identifier.doi10.17863/CAM.35159
dcterms.dateAccepted2018-08-06
rioxxterms.versionofrecord10.1029/2018GC007559
rioxxterms.versionAM
rioxxterms.licenseref.urihttp://www.rioxx.net/licenses/all-rights-reserved
rioxxterms.licenseref.startdate2018-09-01
dc.contributor.orcidKlöcking, M [0000-0002-6592-9270]
dc.contributor.orcidWhite, NJ [0000-0002-4460-299X]
dc.contributor.orcidMaclennan, J [0000-0001-6857-9600]
dc.contributor.orcidFitton, JG [0000-0002-2534-2619]
dc.identifier.eissn1525-2027
rioxxterms.typeJournal Article/Review
cam.issuedOnline2018-09-23
cam.orpheus.successTue Jun 16 10:40:20 BST 2020 - Embargo updated
cam.orpheus.counter12
rioxxterms.freetoread.startdate2019-03-01


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